Secondhand Smoke Killed 1.7 Million in 2023, Study Finds

More than 2.7 billion people worldwide—including 767 million children aged 0 to 14—were exposed to secondhand smoke in 2023, resulting in an estimated 1.7 million deaths, according to a study published Tuesday in the medical journal The Lancet.

Global Burden and Health Impact

The research confirms tobacco remains a leading cause of disease globally. Among the roughly 8 million people who died from smoking-related illnesses in 2023, a significant portion were non-smokers exposed to secondhand smoke. The study identifies secondhand smoke exposure as a globally recognized health hazard, stating unequivocally that “there is no safe level of inhalation.”

Researchers assessed exposure rates and disease burden across 204 countries and territories between 1990 and 2023. Their methodology included reviewing studies indexed in the U.S. National Institutes of Health’s PubMed database and analyzing population-based surveys.

Childhood Exposure and Respiratory Illness

In 2023 alone, secondhand smoke exposure led to an estimated 5.2 million cases of respiratory infection among children. It also contributed to 1.66 million premature deaths and early-onset disability and illness, with ischemic heart disease—the condition arising from insufficient oxygen supply to the heart muscle—topping the list of associated conditions.

The study clarifies that individuals near a smoker inhale both “sidestream smoke,” emitted from burning tobacco products, and “mainstream smoke,” exhaled by the smoker. Sidestream smoke constitutes the majority of inhaled air for non-smokers and is unfiltered, containing higher concentrations—per unit—of toxic and carcinogenic compounds than mainstream smoke.

Trends and Policy Recommendations

Although global smoking prevalence has declined markedly since 1990, the absolute number of people exposed to secondhand smoke has remained stable. This persistence stems from population growth and rising exposure levels in Africa and the Middle East.

The study urges governments to implement stricter measures restricting smoking in public spaces and private homes to strengthen protection against secondhand smoke.